The field of Touch fasteners includes many well known products manufactured under the trade names of Velcro®, Aplix®, YKK®, 3M®, and others. Generally these systems include hook-and-loop types with differentiated portions, or self-engaging types with hermaphroditic portions, each type having well known attributes as well as known drawbacks. Abrasion, clogging, noise, lack of durability, failure when wet, loss of strength, indiscriminate grab, profile thickness, and relative cost are all frequently cited negative attributes of hook-and-loop systems. Mushroom systems and others share similar negative attributes and are limited by the excessive force needed for disengagement and limited cycle life. With regard to disposable products in particular, cost and type of material are significant factors. Abrasion, relative to products in contact with skin, as well as noise are also significant issues for many applications such as personal care products.
Examples of fabric based hook-and-loop fasteners include: DeMestral U.S. Pat. No. 2,717,437; Erb U.S. Pat. No. 3,594,863, Zinke et al U.S. Pat. No. 4,910,062, and Brumlik, U.S. Pat. No. 3,522,637. Examples of molded hook-and-loop hooks include: Kayaki, U.S. Pat. No. 5,067,210, Berger et al, U.S. Pat. No. 5,119,531; and Provost, U.S. Pat. No. 6,526,633. Examples of self-engaging undercut mushroom-like fasteners include: Flanagan, U.S. Pat. No. 3,666,113; Hall, U.S. Pat. No. 4,531,733; and Tuma US2009/0126166 A1. Examples of interengaging bulbous shapes include: Batrell, U.S. Pat. No. 4,946,527, Petersen, U.S. Pat. No. 5,867,876; Clume, U.S. Pat. No. 6,162,040. Chesley et al., U.S. Pat. No. 5,505,747 disclose hooks and mushrooms of various profiles. The prior art also includes other types of interengaging three dimensional shapes, examples of which include: Rouser, U.S. Pat. No. 5,201,101; Murasaki, U.S. Pat. No. 5,457,856; McGanty, U.S. Pat. No. 5,212 855; Berg, et al, U.S. Pat. No. 5,657,516; and Appledorn, U.S. Pat. No. 4,875,259. Ausen, U.S. Pat. No. 7,241,483, more recently discloses a reticulating web with hooks formed by a multiple step process. All typically include a plurality of male to male members locking with multidirectional undercuts or by friction.
Several examples of prior art include relatively thin structures which are formed into fastening elements. Zimmerman, U.S. Pat. No. 3,604,145, discloses a strip of sheet material formed into nesting frictionally connected pins/receptors. Spier, U.S. Pat. No. 4,581,792, discloses a sheet formed uni-directionally undulating structure which is self-engaged by friction along its alternating undulated edges. Cohen, U.S. Pat. No. 4,870,721, discloses hollow pyramids with barbs for fastening with a second receiving structure. Battrell, in U.S. Pat. No. 4,946,527 and U.S. Pat. No. 5,221,276, presents interengaging portions with pluralities of three-dimensionally bulbous shapes with hollow inner cores, apparently formed from a sheet material: the portions are interengaged by compression causing respective bulbous heads to deform and then expand so that their inclined underwalls interface.
Fastening Technologies, including slidingly engaging fasteners and several improvements thereto were introduced by the present inventor, as disclosed in U.S. Pat. Nos. 5,983,467, 7,245,416, AU Patent 60/034,096, EPO Patent 1,011,362, CA Patent 2, 311,306, and other patents pending including Published US application 2008/0018025 A1 concerning methods of making fasteners including die forming methods. Slidingly engaging fasteners (SEFs) comprise generally hermaphroditic arrays of islands with undersides and corresponding receiving apertures between adjacent islands. The islands are connected by sliding correspondent undersides beneath each other until they are stopped at the narrow end of an effectively tapered chamber. Some of the previously disclosed embodiments of SEFs also have included three-dimensional surface modeling to enhance self-alignment, spacing of islands to prevent back sliding, as well as three dimensional aspects to enhance initiation of engagement by compression. However, the thickness of islands is generally equal to the depth of corresponding apertures so that at least minimal shear pressure is required to achieve engagement. For some applications requiring significant flexure, low cost production, relatively small scales, and engagement by simple compression (touch), these previous SEF systems may be less than fully adequate. In particular, an SEF system which is fully self-aligned, which can be engaged solely by touch, which has a generally undulating texture with no exposed edges, and which can be produced of inexpensive materials by die forming would be particularly useful.
A pressure activated self-adhering device also by the present inventor has been published as US 2008/0034560 A1. It includes a plurality of nodules protruding from the interstices of a structural matrix which define receptors for receiving like modules to effect a very low-profile self-engaging fastener with no additive thickness. This system however requires relatively significant compressive engagement pressure and is preferably manufactured by a relatively expensive molding process.
There appears to be a continuing significant need and market for an improved type of self-engaging touch fastener which is easy to use, relatively durable, quiet, non-abrasive to skin, and which could be manufactured at low cost by die cut and formed materials including plastic films.